The following Lost Judgment guide page explains what the access code to the Gambling Hall in Ijincho is.
The Gambling Hall is located in the Red Light District in Ijincho. You must enter the correct access code to enter.
You can get a clue about the access code by eavesdropping on 2 men standing in Fukutoku Park. You will learn from their conversation that the access code is 7120.
At the Gambling Hall, players can purchase special wooden chips needed for gambling games. Prize exchange allows you to exchange points earned during games for interesting items, such as Free Pass Voucher 6.